Comparative Analysis of Hepatitis B Virus Infections in Blood Donors Born Before and After the Implementation of Universal HBV Vaccination in Southern China

Background: In China, the vaccinated blood donors have rapidly increased by recent years, which may impact blood safety. The true prevalence of HBV between vaccinated blood donors and non-vaccinated blood donors should be explored.Study design and methods: The samples of blood donors were collected and detected for serologic markers of HBV in the Shenzhen blood center(SZBC) between Feb 2016 and Jun 2016. The discrepant results were tested with commercial electrochemiluminescence immunoassay (ELCI), alternative MPX ID NAT, nested PCR, and a quantitative real-time polymerase chain reaction (qPCR) assay. HBsAg and anti-HBs were quantified. The serological and molecular characteristics of HBV infected blood donors were analyzed, and the effects on blood safety for donors born before and after the implementation of universal HBV vaccination were compared.Results: Total of 242 reactive by NAT and/or HBsAg ELISA samples from 26318 candidate donors, 192 (0.73%, [95%CI, 0.63-0.84]) HBV+, 131 (0.49%, [95%CI, 0.43-0.59]) HBsAg+, 58 (0.22%, [95%CI,0.17-0.28]) occult hepatitis B infections (OBI) were confirmed respectively. The HBV+ rate in vaccinated donors is lower than in non-vaccinated donors (P<0.05). The HBsAg titers of vaccinated infected blood donors are much higher than non vaccinated infected blood donors. The OBI yield rates in the vaccinated blood donors were 0.11% (7/6422), and significantly lower than the non-vaccinated blood donors (0.26% , 51/19898, P<0.05). There 102/124 (82.3%) samples were genotype B, 22/124 (17.7%) were genotype C respectively. There was no significant difference in the distribution of genotype between non-vaccinated blood donors (B/C,86/17) and vaccinated blood donors (B/C,23/6) (P>0.05). High frequency of vaccine escape mutations M133L (32.4%) and E164G in S region of genotype B strains and substitution L175S (40.9%) related to vaccine escape in S region of genotype C strains were identified.Conclusion: The universal HBV vaccination program markedly reduces the risk of HBV infection in blood donors, and provides a significant guarantee for the safety of blood transfusion. Several important mutations detected related vaccine escape and notable mutations needed further investigated.